I was thinking along similar line. Instead of glass tube, I wonder if we can make the track to be a v-shaped track or bar, much like the Laadegard arm, and have the two rolling bearings riding inside this V-track, which can be made from an aluminum bar. I do realize the vertical movement might be too inhibiting and won't have the rolling smoothness of a glass tube like the Cantus.
An externally hosted image should be here but it was not working when we last tested it.
Or can use a convex bearing to get a better vertical rolling movement.
An externally hosted image should be here but it was not working when we last tested it.
Or the convex bearing on two rods.
An externally hosted image should be here but it was not working when we last tested it.
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Murray et al...
here's a png of the DIY version of the Cantus3 me and Murray started work on last year. This was worked back from a photo, so dims may be wrong. Me and Murray also worked up an external "carriage" type that shows some promise, but may be heavier than the Cantus.
I actually would be interested in contacting Bo directly (I have an interesting for him to ponder).
Directdriver: I can't see why the last type wouldn't work, just seperate the metal rods a little more...
here's a png of the DIY version of the Cantus3 me and Murray started work on last year. This was worked back from a photo, so dims may be wrong. Me and Murray also worked up an external "carriage" type that shows some promise, but may be heavier than the Cantus.
I actually would be interested in contacting Bo directly (I have an interesting for him to ponder).
Directdriver: I can't see why the last type wouldn't work, just seperate the metal rods a little more...
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Stew: a stainless steel tube would do just fine, I don't think that glass has any special advantage. Take a look at the Nottingham arm in the pictures above as this is essentially what you describe though the tube the bearing rides upon is small in diametre.
The advantage that is gained by running inside the tube is that of having geometry and gravity work together to automatically reposition the trolley to its intended position in the tube should the cartridge have to track a severe warp.
Bo's primary goal is to translate as much physical motion (at the stylus tip) into electrical energy (signal output) as is possible. This means that you have to have a rigid system to prevent loss. The horizontal trolley is about as close to this as is possible. The vertical motion through the intended bearing sideways play permits arm rotation which must be there to accommodate record warps yields to the design goal only enough to do the job under real world conditions. The system is non resonant and incredibly rigid.
The advantage that is gained by running inside the tube is that of having geometry and gravity work together to automatically reposition the trolley to its intended position in the tube should the cartridge have to track a severe warp.
Bo's primary goal is to translate as much physical motion (at the stylus tip) into electrical energy (signal output) as is possible. This means that you have to have a rigid system to prevent loss. The horizontal trolley is about as close to this as is possible. The vertical motion through the intended bearing sideways play permits arm rotation which must be there to accommodate record warps yields to the design goal only enough to do the job under real world conditions. The system is non resonant and incredibly rigid.
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Look Moray.....wait 'til you get hold of one of them yourself.
As a highly qualified Mechanical Engineer, I can assure you that using a combination of different materials, (Hardened Steel Balls to Very Hard Glass) has massive benefits in eliminating vibrations, caused by Rolling Friction.
Metal to Metal "Sings". Try a couple of Cymbels!!
And this "Intended bearing sideways play" is just a fairy-tale. The Trolley rotates up the Inside Wall of the Glass Tube to accomandate Record Warps.
LUVP.
As a highly qualified Mechanical Engineer, I can assure you that using a combination of different materials, (Hardened Steel Balls to Very Hard Glass) has massive benefits in eliminating vibrations, caused by Rolling Friction.
Metal to Metal "Sings". Try a couple of Cymbels!!
And this "Intended bearing sideways play" is just a fairy-tale. The Trolley rotates up the Inside Wall of the Glass Tube to accomandate Record Warps.
LUVP.
Peter: my comments here are given in the context of DIY. Most DIY builders do not have the ability to machine a glass tube. A stainless tube can be machined and polished to a precision inside diametre at any good machine shop or by those with the know how and their own equipment. This would I expect result in satisfactory results. I agree that the combination chosen by Bo is probably offers the best outcome and performance for the reasons you stated.
I had mentioned that the trolley would move up the inside of the tube during sever warps. I was under the impression that it was either Rauna or yourself that spoke about the bearings used and that they have built in play in the race to allow for arm motion. If I am in error then I apologize for misleading readers and stand corrected. I will re read correspondence to see where this impression originated.
I had mentioned that the trolley would move up the inside of the tube during sever warps. I was under the impression that it was either Rauna or yourself that spoke about the bearings used and that they have built in play in the race to allow for arm motion. If I am in error then I apologize for misleading readers and stand corrected. I will re read correspondence to see where this impression originated.
look at the statement it is a Cantus (horizontal trolley and bearings)with a tube arm wand which does not sound as good as what Bo does. Discussed this with Bo last year and he went through all sorts of arm wands and said that no matter how he damped a large tube wand the resonance was audible. While Cantus is not so fancy it is a fabulous deal for a great tonearm.
V shaped track plus
Hi all, Been thinking along these lines for a few weeks now since I found a couple of miniature precision ball bearings in the junk box. They felt pretty smooth so today I built up a prototype using left over aluminium v Chanel from a Laadergard experiment. Made one significant change to the idea. Instead of having the bearings run on a metallic surface I cut slips of good old float glass (aka window glass) and glued them to the metal Chanel. Viola! as they say in fractured French. Built up a crude carriage and arm and set the contraption to playing a few records. TT was not level by a long shot. The bearings need to have the old grease flushed out. Maybe get some new ones. The whole jury rig leaves a lot to be desired, but you better beleive it works and sounds great. To crown the insult I was using an old Radio Shack version of the Shure cartridge. Shure isn't an Ortofon OM40 but the sound was surprisingly good. I expect to do some refining and then will write up a more detailed report.
Prior to using the V Chanel I cut a nice slot in a piece of aluminnium tubing and slid in 2 glass pieces. That is what may be a better wat to handle the idea. My only problem was that the bearings on hand were just a tad to big to fit in the tube with the glass pieces installed. Some smaller bearings or bigger tubing should take care of that easily. How about someone else giving this a go?
Bill
Hi all, Been thinking along these lines for a few weeks now since I found a couple of miniature precision ball bearings in the junk box. They felt pretty smooth so today I built up a prototype using left over aluminium v Chanel from a Laadergard experiment. Made one significant change to the idea. Instead of having the bearings run on a metallic surface I cut slips of good old float glass (aka window glass) and glued them to the metal Chanel. Viola! as they say in fractured French. Built up a crude carriage and arm and set the contraption to playing a few records. TT was not level by a long shot. The bearings need to have the old grease flushed out. Maybe get some new ones. The whole jury rig leaves a lot to be desired, but you better beleive it works and sounds great. To crown the insult I was using an old Radio Shack version of the Shure cartridge. Shure isn't an Ortofon OM40 but the sound was surprisingly good. I expect to do some refining and then will write up a more detailed report.
Prior to using the V Chanel I cut a nice slot in a piece of aluminnium tubing and slid in 2 glass pieces. That is what may be a better wat to handle the idea. My only problem was that the bearings on hand were just a tad to big to fit in the tube with the glass pieces installed. Some smaller bearings or bigger tubing should take care of that easily. How about someone else giving this a go?
Bill
Very interesting idea. Any chance you could post a few pics?
I have built the laadegaard arm and while its great sonically, and in daily use, the air compressor bit is a right PITA. A system such as this would be a great step forward. So much so I woul dbe very interested in trying it out for myself. Can I ask, what bearings are you all speaking of, i.e. what would I ask for if I went into my local industrial bearing supplier?
Fran
I have built the laadegaard arm and while its great sonically, and in daily use, the air compressor bit is a right PITA. A system such as this would be a great step forward. So much so I woul dbe very interested in trying it out for myself. Can I ask, what bearings are you all speaking of, i.e. what would I ask for if I went into my local industrial bearing supplier?
Fran
Hi woodturner-fran, And greetings from a former resident of Salthill, Galway.
Here is an update from yesterday's post. Last evening I flushed out all the old grease and dirt from my junkbox bearings and put in just a drop of clock oil. The improvement in smoothness and the reduction in both starting and running torque was immediately obvious. I'm not set up to make any real measurements of these parameters so it will be necessary to go by the way the track and bearings do their job tracking the grooves. It may be that some appropriate grease will be needed to damp out some loosness in the bearings. The ones I have are from New Hampshire Ball Bearing Company, and are marked R-3HH. I also did some more work on the carriage and arm assembly.
PICS are coming soon. Perhaps later on today. In previous post some concern was voiced about vertical tracking of warps. It was pointed out that the bearings would simply ride up the glass wall and down again thus following the warp. This is correct in principle, but I have observed the vertical motion carefully. These bearings are old and of unknown class. The corners of the outer races are beveled slightly and are smooth but not polished. They roll readily on the glass tracks in the horizontal direction but the vertical motion of the bearing is slightly compromised. The inner and outer races do provide smooth and very light motion in the vertical plane, easily enough to follow the normal small warps on sees on records. For extreme warps the bearing will ride up the glass walls as has been described.
So I do not think there is a problem there. If you are buying new bearings I would suggest going for class ABEC 5 or ABEC 7 and if possible with polished and radiused corners on the outer race.
Earlier posts have called the bearings "roller". The pics of the Cantus arm appear to show "ball bearings". Does anyone here really know which type of bearing Cantus uses? Roller or ball?
Slainte,
Bill G.
Thanks Bill,
...all the way along here I thought that the bearings were what I call self-centering. That would allow them to pivot to track warps without moving up the glass tubing wall.
See for eg this bearing:
OK - I know that one is not sealed, and the angle of the inner bit is shown at an extreme level, but you see what I mean. A bearing like that would allow several degrees of vertical movement to ride warps without trying to push the whole assembly up the glass tube. And if the warp pushes the carriage up the wall of the tube, you have to ask what will happen the sound as the carriage returns to the bottom of the glass tube.
Must investigate some of these bearings more closely. I've used large ones before in a lathe, but I wonder if they are available in small sizes.
Fran
...all the way along here I thought that the bearings were what I call self-centering. That would allow them to pivot to track warps without moving up the glass tubing wall.
See for eg this bearing:
An externally hosted image should be here but it was not working when we last tested it.
OK - I know that one is not sealed, and the angle of the inner bit is shown at an extreme level, but you see what I mean. A bearing like that would allow several degrees of vertical movement to ride warps without trying to push the whole assembly up the glass tube. And if the warp pushes the carriage up the wall of the tube, you have to ask what will happen the sound as the carriage returns to the bottom of the glass tube.
Must investigate some of these bearings more closely. I've used large ones before in a lathe, but I wonder if they are available in small sizes.
Fran
Glass Trax
I think the bearing you pictured is called self aligning. I may be wrong there. The point I was making is that the ordinary single row ball bearing has sufficient angular movement of the inner race to accommodate most if not all the warps you will find in all but the worst records. I think the double row would require a good bit more torque to run both in the horizontal plane for record tracking and in the vertical plane for warp tracking. Besides they cost more than single row bearings and may contribute more noise to the system.
I made some pics of the prototype arm (not finished yet) and posted them on my web page. Go to Index of /~bgruhn/audiodiy to view them. I hoped to have the prototype running this evening but we had a very large tree in the neighborhood come crashing down and the power was out for over five hours. All back to normal and tomorrow is another day. I will try attaching the images here as well.
Bill G.
I think the bearing you pictured is called self aligning. I may be wrong there. The point I was making is that the ordinary single row ball bearing has sufficient angular movement of the inner race to accommodate most if not all the warps you will find in all but the worst records. I think the double row would require a good bit more torque to run both in the horizontal plane for record tracking and in the vertical plane for warp tracking. Besides they cost more than single row bearings and may contribute more noise to the system.
I made some pics of the prototype arm (not finished yet) and posted them on my web page. Go to Index of /~bgruhn/audiodiy to view them. I hoped to have the prototype running this evening but we had a very large tree in the neighborhood come crashing down and the power was out for over five hours. All back to normal and tomorrow is another day. I will try attaching the images here as well.
Bill G.
In previous posts some concern was voiced about vertical tracking of warps. It was pointed out that the bearings would simply ride up the glass wall and down again thus following the warp. This is correct in principle, but I have observed the vertical motion carefully. These bearings are old and of unknown class. The corners of the outer races are beveled slightly and are smooth but not polished. They roll readily on the glass tracks in the horizontal direction but the vertical motion of the bearing is slightly compromised. The inner and outer races do provide smooth and very light motion in the vertical plane, easily enough to follow the normal small warps on sees on records. For extreme warps the bearing will ride up the glass walls as has been described.
So I do not think there is a problem there. If you are buying new bearings I would suggest going for class ABEC 5 or ABEC 7 and if possible with polished and radiused corners on the outer race.
Bill G.[/QUOTE]
Evening All,
If you go to www.gis.net/~bgruhn/audiodiy/GlassTraxProto1B.JPG you will see the modifications which make the prototype a functioning arm. The arm wand was shortened and raised in the carriage member to permit lowering the whole thing closer to the TT. Also the arm wand and the counterweight tube were both shortened. The track beam was mounted (hot glue) to a steel disk (wood veneered for another project). This assembly is heavy enough to just sit on the plinth wherever it needs to go. It won't move unless forcibly urged to do so. Then I hooked it up, positioned it roughly by eye and started playing a few records. Still got the RadioShack SHURE cartridge. That will go soon giving way to the ORTOFON OM30. The arm tracked one disk very well. The other disc exhibited some problem with the tracking of the grooves. Soundwise there was no discernible problem, but watching the arm move showed a "stick/slip" motion. The cantilever would follow the groove until enough force built up to move the carriage. Then it would play on until the next sticky spot was found and then repeat. So this needs some work. As I mentioned before, the radiused corners of the bearing outer races are not truly smooth and well polished. My gut feel is that with well finished corner radii this problem will go away. I do not think it is due to flaws in the glass tracks. I'm looking at bearings referred to as track runners and talking to an engineer at one of the bearing companies. Looks like this problem can be easily solved. Found out some more about float glass. That stuff is amazingly smooth and flat, approaching optical tolerances. There should not be a glass surface finish problem. The sound is amazing also. I'm comparing it to a nicely crafted Schroeder clone. No tracking error distortion anywhere on the disk. I do get a little with the pivoted arm. As for subjective assessment, I have not begun to do any careful listening. All I can say is that I like what I'm hearing.
BillG
So I do not think there is a problem there. If you are buying new bearings I would suggest going for class ABEC 5 or ABEC 7 and if possible with polished and radiused corners on the outer race.
Bill G.[/QUOTE]
Evening All,
If you go to www.gis.net/~bgruhn/audiodiy/GlassTraxProto1B.JPG you will see the modifications which make the prototype a functioning arm. The arm wand was shortened and raised in the carriage member to permit lowering the whole thing closer to the TT. Also the arm wand and the counterweight tube were both shortened. The track beam was mounted (hot glue) to a steel disk (wood veneered for another project). This assembly is heavy enough to just sit on the plinth wherever it needs to go. It won't move unless forcibly urged to do so. Then I hooked it up, positioned it roughly by eye and started playing a few records. Still got the RadioShack SHURE cartridge. That will go soon giving way to the ORTOFON OM30. The arm tracked one disk very well. The other disc exhibited some problem with the tracking of the grooves. Soundwise there was no discernible problem, but watching the arm move showed a "stick/slip" motion. The cantilever would follow the groove until enough force built up to move the carriage. Then it would play on until the next sticky spot was found and then repeat. So this needs some work. As I mentioned before, the radiused corners of the bearing outer races are not truly smooth and well polished. My gut feel is that with well finished corner radii this problem will go away. I do not think it is due to flaws in the glass tracks. I'm looking at bearings referred to as track runners and talking to an engineer at one of the bearing companies. Looks like this problem can be easily solved. Found out some more about float glass. That stuff is amazingly smooth and flat, approaching optical tolerances. There should not be a glass surface finish problem. The sound is amazing also. I'm comparing it to a nicely crafted Schroeder clone. No tracking error distortion anywhere on the disk. I do get a little with the pivoted arm. As for subjective assessment, I have not begun to do any careful listening. All I can say is that I like what I'm hearing.
BillG
Hi,
Those are indeed called self-aligning bearings.
Not sure why you'd need them.
You probably don't need V-groove bearings either, they're basically only needed when you need to support both radial and axial loads.
Keep in mind they're basically dual line contact so the contact area with the bearing race is twice the surface arera of a regular bearing.
For those using industrial bearings, have you considered using full ceramic (Si3N4) bearings?
You won't need any sealing nor lubricant and they have extremely low frictional losses. On top of that they're also noticeably lighter than a standard steel bearing.
Cheers,
Those are indeed called self-aligning bearings.
Not sure why you'd need them.
You probably don't need V-groove bearings either, they're basically only needed when you need to support both radial and axial loads.
Keep in mind they're basically dual line contact so the contact area with the bearing race is twice the surface arera of a regular bearing.
For those using industrial bearings, have you considered using full ceramic (Si3N4) bearings?
You won't need any sealing nor lubricant and they have extremely low frictional losses. On top of that they're also noticeably lighter than a standard steel bearing.
Cheers,
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